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Influence of dehydrating agents on the oxidative carbonylation of methanol for dimethyl carbonate synthesis over a Cu/Y-zeolite catalyst

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Chinese Journal of Chemical Engineering 2018年第5期26卷 1059-1063页

作者： Dong-Ho Lee Jiin You Je-Min Woo Jung Yoon Seo young cheol park Jong-Seop Lee Hyunuk Kim Jong-Ho Moon Seung Bin park Greenhouse Gas Laboratory Korea Institute of Energy Research Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and Technology Energy Material Laboratory Korea Institute of Energy Research

The influence of the dehydration by metal oxides on the synthesis of dimethyl carbonate （DMC） via oxidative carbonylation of methanol was studied. A Cu/Y-zeolite catalyst was prepared by the ion exchange method from CuCl2.2H2O and the commercial NH4-form of the Y type zeolite, The catalyst was characterized by X-ray fluorescence （XRF）, N2 adsorption （BET method）, X-ray diffraction （XRD）, and temperature-programmed de- sorption of ammonia （NH3-TPD） to evaluate its Cu and Cl content, surface area, structure, and acidity. Reaction tests were carried out using an autoclave （batch reactor） for 18 h at 403 K and 5.5 MPa （2CH3OH ＋ 1/2O2 ＋ CO （CH3O）2CO ＋ H2O）. The influence of various dehydrating agents （ZnO, MgO, and CaO） was examined with the aim of increasing the methanol conversion （XMeOH, MeOH conversion）. The MeOH conversion increased upon addition of metal oxides in the order CaO 〉〉 MgO 〉 ZnO, with the DMC selectivity （SDMC） following the order MgO 〉 CaO 〉 ZnO. The catalysts and dehydrating agents were characterized before and after the oxidative carbonylation of methanol by thermogravimetric and differential thermogravimetric （TG/DTG）, and XRD to con- firm that the dehydration reaction occurred via the metal oxide （MO ＋ H2O →M（OH）2）. The MeOH conversion increased from 8.7% to 14.6% and DMC selectivity increased from 39.0% to 53.1%, when using the dehydrating azent CaO.

关键词： Carbon monoxide Zeolite Catalyst Dimethyl carbonate Oxidative carbonylation Dehydrating agent

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Ezetimibe improves hepatic steatosis in relation to autophagy in obese and diabetic rats

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World Journal of Gastroenterology 2015年第25期21卷 7754-7763页

作者： Eugene Chang Lisa Kim Se Eun park Eun-Jung Rhee Won-young Lee Ki-Won Oh Sung-Woo park cheol-young park Department of Nutritional Science and Food Management Ewha Womans University Diabetes Research Institute Kangbuk Samsung Hospital Sungkyunkwan University School of Medicine Division of Endocrinology and Metabolism Department of Internal Medicine Kangbuk Samsung Hospital Sungkyunkwan University School of Medicine

AIM: To investigate whether ezetimibe ameliorates hepatic steatosis and induces autophagy in a rat model of obesity and type 2 diabetes. METHODS: Male age-matched lean control LETO and obese and diabetic OLETF rats were administered either PBS or ezetimibe(10 mg/kg per day) via stomach gavage for 20 wk. Changes in weight gain and energy intake were regularly monitored. Blood and liver tissue were harvested after overnight fasting at the end of study. Histological assessment was performed in liver tissue. The concentrations of glucose, insulin, triglycerides(TG), free fatty acids(FFA), and total cholesterol(TC) in blood and TG, FFA, and TG in livertissue were measured. m RNA and protein abundance involved in autophagy was analyzed in the liver. To investigate the effect of ezetimibe on autophagy and reduction in hepatic fat accumulation, human Huh7 hepatocytes were incubated with ezetimibe(10 μmol/L) together with or without palmitic acid(PA, 0.5 mmol/L, 24 h). Transmission electron microscopy(TEM) was employed to demonstrate effect of ezetimibe on autophagy formation. Autophagic flux was measured with bafilomycin A1, an inhibitor of autophagy and following immunoblotting for autophagy-related protein ***: In the OLETF rats that received ezetimibe(10 mg/kg per day), liver weight were significantly decreased by 20% compared to OLETF control rats without changes in food intake and body weight(P < 0.05). Lipid parameters including TG, FFA, and TC in liver tissue of ezetimibe-administrated OLETF rats were dramatically decreased at least by 30% compared to OLETF controls(P < 0.01). The serum glucose, insulin, HOMA-IR, and lipid profiles were also improved by ezetimibe(P < 0.05). In addition, autophagy-related m RNA expression including ATG5, ATG6, and ATG7 and the protein level of microtubule-associated protein light chain 3(LC3) were significantly increased in the liver in rats that received ezetimibe(P < 0.05). Likewise, for hepatocytes cultured in vitro,

关键词： Autophagy Ezetimibe Hepatic steatosis Nonalcoholic fatty liver disease

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Verification of Beam Models for Ionic Polymer-Metal Composite Actuator

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Journal of Bionic Engineering 2009年第3期6卷 232-238页

作者： Hoon cheol park Quoc Viet Nguyen Jang Woo Lee young Tai Yoo Artificial Muscle Research Center Konkuk University Department of Advanced Technology Fusion Konkuk University Department of Materials Chemistry and Engineering Konkuk University

Ionic Polymer-Metal Composite (IPMC) can work as an actuator by applying a few voltages.A thick IPMC actuator,where Nafion-117 membrane was synthesized with polypyrrole/alumina composite filler,was analyzed to verify the equivalent beam and equivalent bimorph beam *** blocking force and tip displacement of the IPMC actuator were measured with a DC power supply and young's modulus of the IPMC strip was measured by bending and tensile tests *** calculated maximum tip displacement and the young's modulus by the equivalent beam model were almost identical to the corresponding measured *** element analysis with thermal analogy technique was utilized in the equivalent bimorph beam model to numerically reproduce the force-displacement relationship of the IPMC *** results by the equivalent bimorph beam model agreed well with the force-displacement relationship acquired by the measured *** is confirmed that the equivalent beam and equivalent bimorph beam models are practically and effectively suitable for predicting the tip displacement,blocking force and young's modulus of IPMC actuators with different thickness and different composite of ionic polymer membrane.

关键词： jonic polymer-metal composite beam model displacement force

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New separation algorithm for touching grain kernels based on contour segments and ellipse fitting

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第1期12卷 54-61页

作者： Lei YAN cheol-Woo park Sang-Ryong LEE Choon-young LEE School of Mechanical Engineering Kyungpook National University Daegu 702-701 Korea School of Technology Beijing Forestry University Beijing 100083 China

A new separation algorithm based on contour segments and ellipse fitting is proposed to separate the ellipse-like touching grain kernels in digital *** image is filtered and converted into a binary image *** the contour of touching grain kernels is extracted and divided into contour segments (CS) with the concave points on *** next step is to merge the contour segments,which is the main contribution of this *** distance measurement (DM) and deviation error measurement (DEM) are proposed to test whether the contour segments pertain to the same kernel or *** they pass the measurement and judgment,they are merged as a new *** with these newly merged contour segments,the ellipses are fitted as the representative ellipses for touching *** verify the proposed algorithm,six different kinds of Korean grains were *** results showed that the proposed method is efficient and accurate for the separation of the touching grain kernels.

关键词： Separation algorithm Touching grains Contour segments Ellipse fitting

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Curcumin attenuates the release of pro-inflammatory cytokines in lipopolysaccharide-stimulated BV2 microglia

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Acta Pharmacologica Sinica 2007年第10期28卷 1645-1651页

作者： Jae-dong LEE cheol park Yung hyun CHOI Gi-young KIM Department of Microbiology College of Natural Sciences Pusan National UniversityBusan 609-735 Department of Biochemistry Dongeui University College of Oriental MedicineBusan 614-054Korea Faculty of Applied Marine Science Cheju National UniversityJeju-siJeju Special Self-Governing Province 690-756Korea

Aim:Pro-inflammatory mediators,such as prostaglandin E2（PGE2） and nitric oxide（NO）,and pro-inflammatory cytokines such as interleukin （IL）-1β,IL-6,and TNF-α,play pivotal roles in brain *** anti-inflammatory properties are knownto be associated with significant reductions in pro-inflammatory mediators in *** the present study we investigate whether the effects of curcumin onthe production of pro-inflammatory mediators in lipopolysaccharide （LPS）-stimu-lated BV2 ***:Curcumin were administered and their effects onLPS-induced pro-inflammatory mediators were monitored by Western blottingand ***:Curcumin significantly inhibited the release of NO,PGE2,and pro-inflammatory cytokines in a dose-dependent *** alsoattenuated the expressions of inducible NO synthase and cyclooxygenase-2 mRNAand protein ***,curcumin suppressed NF-kB activation via thetranslocation of p65 into the *** data also indicate that curcumin exertsanti-inflammatory properties by suppressing the transcription of proinflammatorycytokine genes through the NF-kB signaling ***:Anti-inflam-matory properties of curcumin may be useful for treating the inflammatory anddeleterious effects of microglial activation in response to LPS stimulation.

关键词： curcumin inducible nitric oxide synthase cyclooxygenase-2 pro-inflammatory cytokines NF-kB

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Parameter estimation for building energy models using GRcGAN

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Building Simulation 2023年第4期16卷 629-639页

作者： Hansol Shin cheol-Soo park Department of Architecture and Architectural Engineering College of EngineeringSeoul National UniversitySeoul08826R.O.Korea Institute of Construction and Environmental Engineering Institute of Engineering ResearchCollege of EngineeringSeoul National UniversitySeoul08826R.O.Korea

Parameter estimation methods can be classified into(1)manual(trial-and-error),(2)numerical optimization(optimization,sampling),(3)Bayesian inference(Bayes filter,Bayesian calibration),and(4)machine learning(generative model).Bayesian calibration has been widely used because it can capture stochastic nature of uncertain ***,the results of Bayesian calibration could be biased by(1)the prior distribution assumed by the expert’s subjective judgment;(2)the likelihood function that cannot always describe the true likelihood;and(3)the posterior distribution approximation method,such as the Markov Chain Monte Carlo,which requires significant computation *** overcome this,a new approach using a generator-regularized continuous conditional generative adversarial network(GRcGAN)is presented in this *** target parameters of the DOE reference building model were *** was trained to estimate uncertain parameters using simulated monthly electricity and gas *** can successfully estimate five uncertain parameters based on 1,000 training data *** proposed approach presents a potential for stochastic parameter estimation.

关键词： generative adversarial networks generative model parameter estimation inverse problem model calibration parameter uncertainty

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Size-dependent transition of the deformation behavior of Au nanowires

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Nano Research 2015年第3期8卷 941-947页

作者： Na-young park Ho-Seok Nam PiI-Ryung Cha Seung-cheol Lee School of Advanced Materials Engineering Kookmin University Seou1136-702 R. O. Korea Future Convergence Research Division Korea Institute of Science and Technology (KIST) Seou1136-791 R. O. Korea Indo-Korea Science and Technology Center Korea Institute of Science and Technology (KIST) Seou1136-791 R. O. Korea

Inspired by the controversy over tensile deformation modes of single-crystalline 〈110〉/{111} Au nanowires, we investigated the dependency of the deformation mode on diameters of nanowires using the molecular dynamics technique. A new criterion for assessing the preferred deformation mode-slip or twin propagation--of nanowires as a function of nanowire diameter is presented. The results demonstrate the size-dependent transition, from superplastic deformation mediated by twin propagation to the rupture by localized slips in deformed region as the nanowire diameter decreases. Moreover, the criterion was successfully applied to explain the superplastic deformation of Cu nanowires.

关键词： Au nanowire molecular dynamics size-dependent transition tensile deformationmechanism

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The electronic structure and intervalley coupling of artificial and genuine graphene superlattices

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Nano Research 2016年第4期9卷 1101-1115页

作者： Pilkwang Kim cheol-Hwan park Department of Physics and Astronomy Seoul National University Seou108826 Republic of Korea

The so-called artificial graphene is an artificial material whose low-energy carriers are described by the massless Dirac equation. Applying a periodic potential with triangular symmetry to a two-dimensional electron gas is one approach to make such a material. According to recent experimental results, it is now possible to realize artificial graphene in the lab and to even apply an additional lateral, one-dimensional periodic potential to it. We name the latter system an artificial graphene superlattice in order to distinguish it from a genuine graphene superlaedce made from graphene. In this study, we investigate the electronic structure of artificial graphene superlattices, which exhibit the emergence of energy band gaps, merging and splitting of the Dirac points, etc. Then, from a similar investigation on genuine graphene superlattices, we show that many of these features originate from the coupling between Dirac fermions residing in two different valleys--the intervaUey coupling. Furthermore, contrary to previous studies, we find that the effects of intervalley coupling on the electronic structure cannot be ignored, irrespective of the length of the spatial period of the superlattice.

关键词： graphene artificial graphene graphene superlattice intervaUey coupling

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Design and Demonstration of a Locust-Like Jumping Mechanism for Small-Scale Robots

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Journal of Bionic Engineering 2012年第3期9卷 271-281页

作者： Quoc-Viet Nguyen Hoon cheol park Department of Advanced Technology Fusion Konkuk University Seoul 143-701 Republic of Korea

A jumping mechanism can be an efficient mode of motion for small robots to overcome large obstacles on the ground and rough terrain. In this paper, we present a 7 g prototype of locust-inspired jumping mechanism that uses springs, wire, reduction gears, and a motor as the actuation components. The leg structure and muscles of a locust or grasshopper were mimicked using springs and wire, springs for passive extensor muscles, and a wire as a flexor muscle. A small motor was used to slowly charge the spring through a lever and gear system, and a cam with a special profile was used as a clicking mechanism for quick release of elastic energy stored in the springs to create a sudden kick for a quick jump. Performance analysis and experiments were conducted for comparison and performance estimation of the jumping mechanism prototype. Our prototype could produce standing jumps over obstacles that were about 14 times its own size （approximate to 71 cm） and a jumping distance of 20 times its own size （approximate to 100 cm）.

关键词： biomimetics locust jumping mechanism passive tibia extensor muscle

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Generation of Control Moments in an Insect-like Tailless Flapping-wing Micro Air Vehicle by Changing the Stroke-plane Angle

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Journal of Bionic Engineering 2016年第3期13卷 449-457页

作者： Hoang Vu Phan Hoon cheol park Artificial Muscle Research Center Konkuk University Seoul 143-701 South Korea Deptment of Advanced Technology Fusion Konkuk University Seoul 143-701 South Korea

We propose a control moment generator to control the attitude of an insect-like tailless Flapping-wing Micro Air Vehicle （FW-MAV）, where the flapping wings simultaneously produce the flight force and control moments. The generator tilts the stroke plane of each wing independently to direct the resultant aerodynamic force in the desired direction to ultimately generate pitch and yaw moments. A roll moment is produced by an additional mechanism that shifts the trailing edge, which changes the wing rotation angles of the two flapping wings and produces an asymmetric thrust. Images of the flapping wings are captured with a high-speed camera and clearly show that the FW-MAV can independently change the stroke planes of its two wings. The measured force and moment data prove that the control moment generator produces reasonable pitch and yaw moments by tilting the stroke plane and realizes a roll moment by shifting the position of the trailing edge at the wing root.

关键词： insect-like Flapping-wing Micro Air Vehicle (FW-MAV) control mechanism stroke plane beetle flight

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